The present invention relates to liquid metering pumps, and has for an object, improvements therein.
To inject metered amounts of liquid into another liquid it is known to use metering pumps which consist of a cylinder in which a piston moves. The piston draws in the liquid to be metered and delivers it to another container. This container may in particular be an injection device as described in French patent No. 2,205,361.
However, such a metering pump is chiefly useful for obtaining relatively large volumes of liquid and is not suited to small amounts which have to be very accurately metered.
It is an object of this invention to minimize or overcome this disadvantage and to allow very small throughputs to be obtained.